Effect of ischemia on nucleosides and bases in rat liver and hepatoma 3924A.

A high-pressure liquid chromatographic method was developed which achieved a separation and quantitation of 20 biologically important nucleosides and bases. The concentrations of pyrimidine nucleosides and bases, namely deoxycytidine, cytosine, cytidine, uracil, and uridine (22.6, 10.1, 5.2, 2.9, and 2.4 nmol/ml, respectively) were high in plasma, whereas purine nucleosides and bases were present in concentrations less than 2.5 nmol/ml. In erythrocytes, the pools of xanthine, hypoxanthine, and xanthosine were 32-, 27-, and 22-fold larger, respectively, whereas cytidine, uridine, and deoxycytidine were only 21, 12, and 5% of plasma concentrations. The results suggest a compartmental system for transport of some of the purine and pyrimidine nucleosides and bases in the whole blood. Studies on the effect of ischemia on nucleoside and base pools in rat liver indicated marked increases within 30 s in the concentrations of adenine, adenosine, inosine, hypoxanthine, uridine, and xanthine, whereas in hepatoma the effects were less pronounced. By 2 and 5 min ischemia these perturbations were most marked in both liver and hepatoma. These results indicate a need for rapid freeze-clamp preparation of tissue samples to obtain precise and repeatable results in the determination of tissue nucleoside and nucleobase concentrations.

Absence of N-ras mutations in myeloid and lymphoid blast crisis of chronic myeloid leukemia.

Mutations within N-ras oncogene codons 12, 13, and 61 occur in approximately 25-30% of patients with acute nonlymphocytic leukemia and at a lower frequency (6-20%) in patients with acute lymphocytic leukemia. Moreover, N-ras mutations have been described in patients with chronic myeloid leukemia (CML) in blast crisis but have not been observed during the chronic phase of the disease. In view of the morphological and clinical similarities between acute leukemia and the blast crisis of CML, the question was raised whether the presence of N-ras mutations is associated with the phenotype of acute leukemia. We investigated leukemic cells from 100 patients with CML for the presence of N-ras mutations in the mutational hot spot codons. The cases analyzed included 87 diagnosed with different types of blast crisis and 13 cases in accelerated or chronic phase of the disease. Fragments from N-ras exons I and II containing the codons of interest were amplified by polymerase chain reaction and analyzed for the presence of point mutations by three different technical approaches, including specific oligonucleotide hybridization, direct sequencing, and single-strand conformation polymorphism analysis. N-ras mutations were not detected in any of the CML patients investigated. Only one patient, in whom the initial diagnosis of CML-blast crisis had been revised to chronic myelomonocytic leukemia, displayed an N-ras mutation within codon 13. Our data strongly suggest that N-ras mutations do not play a role in myeloid or lymphoid blast crisis of CML.

Purine metabolism of human glioblastoma in vivo.

The aim of this study was to identify targets for rational chemotherapy of glioblastoma. In order to elucidate differences in the biochemistry of tumor and normal human brain, in vivo pool sizes of purine nucleotides, nucleosides, and nucleobases and of purine metabolizing enzymes in biopsy material from 14 grade IV astrocytomas and 4 normal temporal lobe samples were analyzed. Specimens were collected during surgery using the freeze-clamp sampling technique and analyzed by high pressure liquid chromatography. Total purine nucleotides, adenylates, and guanylates in the tumors were 2186, 1865, and 310 nmol/g (wet weight), respectively, which corresponds to 61, 60, and 71% of normal brain tissue concentrations. Relative to normal brain the tumors had significantly lower ATP and GTP levels, essentially normal pool sizes of purine nucleosides and bases, unchanged activities of the salvage enzymes hypoxanthine-guanine phosphoribosyltransferase, adenine phosphoribosyltransferase, and adenosine kinase (659, 456, and 98 nmol/h/mg protein, respectively) and 4-fold higher activities of IMP dehydrogenase (11.6 nmol/h/mg protein); the latter is the rate limiting enzyme for guanylate de novo synthesis. IMP pools in the tumors were 64% of values in normal brain. Modulation of the guanylate pathway in glioblastoma by inhibition of IMP dehydrogenase with tumor specific agents such as tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide) appears to be a rational therapeutic approach. Preliminary in vitro experiments with normal and malignant tissue specimens from 2 additional patients revealed that significant amounts of the active metabolite thiazole-4-carboxamide adenine dinucleotide are formed from tiazofurin. At a concentration of 200 microM this drug was able to deplete guanylate pools in the tumors to a median of 54% of phosphate buffered saline treated controls. Flux studies with [14C]formate showed that tiazofurin strongly inhibited de novo synthesis of guanylates in glioblastoma to an average of 10% of controls. This effect was more pronounced in the tumors as compared to normal brain. No inhibition of salvage of [14C]guanine by tiazofurin could be observed in normal and malignant tissues. Supportive measures have to be considered to inhibit the highly active salvage enzyme hypoxanthine-guanine phosphoribosyltransferase that can partly antagonize a tiazofurin induced decrease in guanine nucleotides.

p53 mosaicism with an exon 8 germline mutation in the founder of a cancer-prone pedigree.

Changes in the tumor-suppressor gene p53 are frequently acquired during the course of malignant development of human tumors. Recently, constitutional heterozygous mutations in p53 exon 7 have been identified as the primary cause of cancer predisposition in cases of the familial Li-Fraumeni cancer syndrome. These findings underline the need for extensive mutation screening in families with high cancer incidence. This report describes the detection and follow-up by two-dimensional single-strand conformation polymorphism analysis (2DSSCP) of a new germline mutation of p53 exon 8 in a case of suspected Li-Fraumeni syndrome. Although a high cancer incidence had been reported in the family history of the father of siblings suffering from brain tumor and rhabdomyosarcoma, a constitutional heterozygous p53 mutation was identified only in the affected children. Retrospective analysis of archival tissue of a half-sister who died several years ago from a tumor of previously uncertain diagnosis revealed the same mutation. The mutation had therefore occurred in the germ cells of the mother, who thus appears to be a mosaic. The cancer predisposition of the paternal ancestors must have been due to other factors.

Hyaluronidase additional to standard chemotherapy improves outcome for children with malignant brain tumors.

Ex vivo experiments with vital brain tumor samples show that hyaluronidase enhances the permeation of carboplatin into tumor tissue with a matrix rich in hyaluronic acid. We achieved long-lasting second remissions for children with relapsed malignant brain tumors treated with carboplatin, etoposide and this enzyme. Thereafter, we initiated a pilot study where we added hyaluronidase to the first line standard therapy to prevent the deadly relapses right from the beginning. All 19 patients with malignant brain tumors admitted to our pediatric neurooncological center from 1992 to 1994 were included in the study. Kaplan-Meier estimation of event-free survival and overall survival after 3 years follow-up indicates a significantly better outcome for the hyaluronidase-treated group. The children receiving supportive hyaluronidase suffered significantly less relapses (P = 0.034) and had a significantly better chance for survival (P = 0.045) compared to the historical control of 21 children treated with the same standard regimen but without supportive hyaluronidase (product limit analysis and the log-rank test, P < 0.05). Children aged >3 years receiving hyaluronidase together with primary treatment seemed to gain the most benefit.

Selective sensitivity to tiazofurin of human leukemic cells.

This study reports the selective sensitivity to tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide, NSC-286193) of human leukemic leukocytes as compared to normal ones in bone marrow and peripheral blood samples by comparing the production of the active metabolite, thiazole-4-carboxamide adenine dinucleotide (TAD), from labeled tiazofurin and the depression of GTP concentration. When labeled tiazofurin was incubated with leukocytes obtained from healthy volunteers or from leukemic patients (acute non-lymphocytic leukemia or acute lymphoblastic leukemia), the TAD production was 27.0 +/- 8.3, 551.3 +/- 71.8 and 755.9 +/- 94.1 pmoles/10(9) cells per hr, respectively. Thus, the leukemic cells produced over 20-fold higher concentrations of TAD than the normal leukocytes. Incubation with tiazofurin in leukemic leukocytes decreased the GTP pools (to 48-79%), whereas there was no change in the normal leukocytes. These results indicate a selectivity of response to tiazofurin in human normal and leukemic leukocytes. The procedure reported in this work may be suitable as a rapid predictive test for the sensitivity of leukemic leukocytes to tiazofurin. Such a diagnostic test should be helpful in identifying neoplastic cells sensitive to tiazofurin in the Phase II trials now being developed.

Mechanism of resistance to tiazofurin in hepatoma 3924A.

Tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide, NSC-286193) has shown potent cytotoxic and antitumor activity against hepatoma 3924A carried in the rat [Lui et al. J. biol. Chem. 259, 5078 (1984)]. However, eventually the tumor emerged, proliferated and killed the host. To throw light on the factors that play a role in the resistance to this drug, a tiazofurin-induced resistant hepatoma 3924A line in culture was produced, and its biochemical and pharmacological pattern was examined. Resistance in hepatoma cells was expressed by a reprogramming of gene expression that entailed the display of a program of multiple biochemical alterations. In the resistant cells the activity of IMP dehydrogenase, the target enzyme of tiazofurin, was increased 2- to 3-fold. The steady-state guanylate pools were elevated 3-fold, and there was a decrease in the de novo synthesis of guanylate. There was an expansion of guanylate salvage, which could circumvent inhibition of de novo guanylate synthesis by tiazofurin. For the first time in studies on the resistance of different cell lines to tiazofurin, reduced tiazofurin transport (to 50%) in resistant hepatoma cells was identified which might account for the decreased concentration (50%) of the active metabolite, thiazole-4-carboxamide adenine dinucleotide (TAD), in these cells. NAD pyrophosphorylase activity also decreased to 53% of that of the sensitive line, which was responsible, in part at least, for the decreased TAD concentration of the resistant cells. When resistant cells were cultured in the absence of tiazofurin, resistance to the drug gradually decreased, and by 50 passages sensitivity returned. Resistance to tiazofurin in hepatoma cells appears to be a drug-induced metabolic adaptation which involves alterations in the activity of the target enzyme, in the transport and concentration of the drug and the active metabolite, and an increase of guanylate concentration and guanine salvage capacity.

Synergistic action of tiazofurin with hypoxanthine and allopurinol in human neuroectodermal tumor cell lines.

The activity of IMP dehydrogenase (EC 1.2.1.14), the key enzyme of de novo guanylate biosynthesis, was shown to be increased in tumor cells. Tiazofurin (TR), a potent and specific inhibitor of this enzyme, proved to be effective in the treatment of refractory granulocytic leukemia in blast crisis. We examined the effects of tiazofurin as a single agent and in combination with hypoxanthine and allopurinol in six different neuroectodermal tumor cell lines, the STA-BT-3 and 146-18 human glioblastoma cell lines, the SK-N-SH, LA-N-1 and LA-N-5 human neuroblastoma cell lines, and the STA-ET-1 Ewing tumor cell line. Tiazofurin inhibited tumor cell growth with IC50 values between 2.2 microM (LA-N-1 cell line) and 550 microM (LA-N-5 cells) and caused a significant decrease of intracellular GTP pools (GTP concentrations decreased to 39-79% of control). Incorporation of [8-14C]guanine into GTP pools was determined as a measure of guanylate salvage activity; incubation with 100 microM hypoxanthine caused a 62-96% inhibition of the salvage pathway. Incubation with tiazofurin (100 microM) and hypoxanthine (100 microM) synergistically inhibited tumor cell growth, and the addition of allopurinol (100 microM) strengthened these effects. Therefore, this drug combination, inhibiting guanylate de novo and salvage pathways, may prove useful in the treatment of human neuroectodermal tumors.

Schedule-dependent synergistic action of tiazofurin and dipyridamole on hepatoma 3924A cells.

Tiazofurin is an oncolytic nucleoside analog that has shown therapeutic activity in end-stage acute non-lymphocytic leukemia and in chronic granulocytic leukemia in blast crisis. Tiazofurin is anabolized to the active metabolite, TAD, which inhibits IMP dehydrogenase activity, leading to a reduction in guanylate pools and to the cessation of neoplastic cell proliferation. The drug exhibits potent cytostatic and cytotoxic activity against hepatoma 3924A cells in culture. In growth-inhibition and clonogenic assays, the 50% inhibitory concentration of tiazofurin was 3.8 and 4.2 microM, respectively. Dipyridamole, an inhibitor of nucleoside transport, curtails the salvage of nucleosides and bases for nucleotide biosynthesis. Dipyridamole exhibited cytotoxicity against hepatoma 3924A cells, with an LC50 of 24 microM and an IC50 of 29 microM being recorded. A combination of tiazofurin and dipyridamole provided synergistic cytotoxicity in hepatoma 3924A cells in culture. This synergistic activity was dependent on the order of addition of the drugs. Simultaneous addition of the two drugs produced antagonism, whereas preincubation of cells with tiazofurin or dipyridamole followed by addition of the second drug resulted in synergy. TAD concentrations were significantly higher (129% and 135%) in cells that had been pretreated with tiazofurin or dipyridamole before the addition of the second agent as compared with cells that had been treated simultaneously (113%). These studies indicate the importance of the order of the addition of drugs to obtain a synergistic response in combination chemotherapy and suggest the need for a careful selection of drug modulation in clinical trials of tiazofurin and dipyridamole.

Oncolytic activity and mechanism of action of a novel L-cysteine derivative, L-cysteine, ethyl ester, S-(N-methylcarbamate) monohydrochloride.

A study on the oncolytic activity of the L-cysteine derivative L-cysteine, ethyl ester, S-(N-methylcarbamate) monohydrochloride (NSC 303861), revealed that the drug caused complete regression of the MX-1 human mammary tumor xenograft. The compound also exhibited moderate antitumor activity against murine leukemia P388 (T/C value of 169% at a daily dose of 400 mg/kg) and against M5076 sarcoma (T/C value of 135% at a daily dose of 600 mg/kg). The drug was inactive against B16 melanoma, Lewis lung, colon 38 and CD8F1 mammary carcinomas. The compound exhibited significant cytotoxicity against hepatoma 3924A cells in culture (LC50 = 6 microM). Studies on the mechanism of action revealed that the cytotoxicity of the drug could be partially abrogated by protecting hepatoma 3924A cells in culture with L-glutamine. At 6 h after injection of the compound (400 mg/kg) into rats bearing hepatoma 3924A, the pools of L-glutamine and L-glutamate in the tumor decreased to 33% and 71%, respectively, of control levels; the drug selectively inhibited the activities of L-glutamine-requiring enzymes of purine nucleotide biosynthesis, amidophosphoribosyltransferase, FGAM synthase, and GMP synthase, to 21%, 1%, and 69%, respectively, without significantly altering the activities of pyrimidine biosynthetic enzymes, carbamoylphosphate synthase II and CTP synthase. Measurement of the nucleotide concentrations further corroborated the actions of the drug on the purine nucleotide biosynthetic enzyme activities. Drug injection (400 mg/kg) in the hepatoma 3924A-bearing rats reduced the concentrations of IMP in the tumor to 52%, those of total adenylates to 52%, those of total guanylates to 57%, and those of NAD to 73%, without significantly perturbing the pyrimidine nucleotide pools. Studies on the mechanism of action of the L-cysteine derivative suggested that the compound behaved as an L-glutamine antagonist, selectively acting on the enzymes of purine nucleotide biosynthesis.

Targets and markers of selective action of tiazofurin.

The molecular correlation concept proposed that IMP dehydrogenase activity should be a sensitive target of chemotherapy. This hypothesis received support from an array of evidence. IMP dehydrogenase has the lowest activity in purine biosynthesis; it is the rate-limiting enzyme in GTP production; the enzymic activity is transformation-and progression-linked; it is elevated in all examined animal and human neoplastic cells. The activity of GMP synthetase and the concentrations of GMP and dGTP were increased in cancer cells. Whereas guanine salvage has a high potential activity, the low guanine content may well curtail actual salvage capacity. Ribonucleotide reductase activity was two orders of magnitude lower than that of IMP dehydrogenase. Tiazofurin, a C-nucleoside, had marked cytotoxicity on hepatoma cells in vitro and was the first drug that as a single agent profoundly inhibited the proliferation of the subcutaneously inoculated solid hepatoma 3924A in the rat. The impact of tiazofurin administration in hepatoma cells was revealed in a cascade of biochemical alterations involving primary, secondary and tertiary targets and markers of this drug action. The primary target was IMP dehydrogenase where the active metabolite of tiazofurin, TAD, was thought to be absorbed to the NADH site of the enzyme. As a consequence, the enzymic activity declined rapidly to about 30-40% and returned to normal range by 36 to 48 hr after injection. The secondary targets and markers are the profoundly decreased pools of guanylates (GMP, GDP, GTP). Concurrently, the concentrations of IMP and PRPP were increased 8- to 15-fold. The elevated IMP pools were attributed to the de-inhibition of the AMP deaminase activity subsequent to the decline in GTP concentration. The rise in PRPP pools was attributed to the selective inhibition of GPRT and HPRT activities by the high IMP pool which did not affect APRT activity. This interpretation is supported by the 6- to 8-fold increase in the concentrations of guanine and hypoxanthine and the lack of change in the adenine pools inthe hepatomas after tiazofurin administration. The marked drop in NAD concentration which was drug dose- and time-dependent is attributed to the competition for NAD pyrophosphorylase activity by the precursors of NAD and tiazofurin monophosphate. The tertiary targets were dominated by the profound alterations in the concentrations of the dNTPs. This was characterized by a rapid and persistent drop (for 3 days) of the dGTP pool. The concentrations of dATP and dCTP also declined, but these alterations were less pronounced and the pools returned to normal after 2 days.(ABSTRACT TRUNCATED AT 400 WORDS)

Salvage pathways as targets of chemotherapy.

This paper discussed the significance of the activities of purine and pyrimidine salvage enzymes in cancer cells and the targeting against them of chemotherapy. 1. The activities of salvage enzymes in the rat liver were orders of magnitude higher than those of the rate-limiting enzymes of de novo biosynthesis. A similar relationship was observed in rat hepatomas of different growth rates and in primary colon carcinoma in human. 2. The concentrations of nucleosides and nucleobases were measured in plasma, liver and hepatoma 3924A in the rat. The freeze-clamp method was required to determine the concentrations of these precursors in rat liver and hepatoma in a reliable and precise fashion because ischemia markedly altered the concentrations of nucleosides, nucleobases and, as shown earlier, nucleotides in these tissues. The results indicated that the liver markedly concentrated the purine precursors, hypoxanthine, guanine and adenine, but not thymidine, which was one-third that of the plasma. Uridine and deoxycytidine occurred in the same concentration as in plasma, but cytidine was 3-fold higher in liver. In the hepatoma in comparison to the liver the concentrations of the nucleosides and bases were altered and for some of the changes the enzymic differences between liver and hepatoma appeared to be accountable. 3. Kinetic parameters for purine and pyrimidine synthetic enzymes and for the substrates and co-factors were determined in liver and hepatoma 3924A. When enzymic activities were calculated at the tissue steady-state concentrations of the various ligands, the activities of the salvage enzymes were markedly higher than those of the rate-limiting enzymes. 4. Hepatoma cells were highly sensitive to the action of the transport inhibitor, dipyridamole, in lag and log phases. However, plateau phase cells lost their sensitivity to dipyridamole. 5. Amphotericin B rendered plateau phase cells sensitive to the inhibitory action of dipyridamole for the incorporation of thymidine. 6. Amphotericin B enhanced cytotoxicity of dipyridamole in hepatoma and human colon cancer HT-29 cells. 7. In these studies we discovered the decreased responsiveness to dipyridamole of plateau phase cells and the ability of amphotericin B to restore the sensitivity. Moreover, dipyridamole and amphotericin B were synergistic in their cytotoxic action in rat hepatoma cells and human colon cancer cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation of purine and pyrimidine metabolism by insulin and by resistance to tiazofurin.

The purpose of this investigation was to elucidate the factors that regulate the pattern of gene expression in purine and pyrimidine metabolism in normal liver and hepatoma. For this purpose, the action of a hormone, insulin, and the development of resistance to a chemotherapeutic agent, tiazofurin, were studied. This investigation brought detailed evidence showing that in the rat insulin exerted a profound effect on liver purine and pyrimidine metabolism by regulating the concentrations of nucleotides through controlling the activities of strategic enzymes involved in their biosynthesis. When rats were made diabetic by alloxan treatment, in the average liver cell concentrations of ATP, GTP, UTP and CTP decreased to 66, 62, 54 and 63%, respectively, of those of normal liver. Administration of insulin for 2 days returned the hepatic nucleotide concentrations to normal range; further insulin treatment for an additional 5 days raised the concentrations of ATP, GTP, UTP and CTP to 197, 352, 412 and 792% of values observed in the liver of diabetic rats. In diabetic rats the hepatic activities of OMP decarboxylase, orotate phosphoribosyltransferase, uridine phosphorylase, uridine-cytidine kinase and uracil phosphoribosyltransferase decreased to 44, 48, 70, 36 and 41% of the activities of normal liver. Insulin treatment for 2 days returned activities to normal range. Continued insulin treatment for an additional 5 days increased the enzymic activities to 3.9- to 5.3-fold of those of the liver of the diabetic rats. The regulation by insulin treatment of the activities of enzymes of de novo and salvage synthesis of UMP should explain, in part at least, the decline and increase of the uridylate pool in diabetes and after insulin treatment. In the diabetic rat hepatic CTP synthetase, the rate-limiting enzyme of CTP biosynthesis, decreased to 53% and insulin administration for 2 days restored activity to normal range. Insulin treatment for an additional 5 days increased the synthetase activity to 4-fold of the values of the diabetic liver. Thus, the behavior of liver CTP synthetase activity is tightly linked with that of the CTP pool. In the diabetic rat liver, the activity of IMP dehydrogenase, the rate-limiting enzyme of GTP biosynthesis, decreased to 24% of that of the normal liver. Insulin administration for 2 days returned the activity to normal range, yielding a 4.5-fold increase in the activity from the diabetic to the insulin-treated state.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell cycle dependent regulation of IMP dehydrogenase activity and effect of tiazofurin.

The activity of IMP dehydrogenase (IMP DH), the rate-limiting enzyme of de novo GTP biosynthesis, was shown to be increased in cancer cells. Tiazofurin, an inhibitor of IMP dehydrogenase, proved to be an effective agent in the treatment of refractory granulocytic leukemia. To examine the cell cycle dependent alterations of GTP synthesis and sensitivities to tiazofurin, we measured IMP DH activities and GTP pools, as well as the effects of tiazofurin on cell cycle phase enriched HL-60 cells. We now show that IMP DH activities and GTP concentrations are increased in S-phase enriched fractions of HL-60 cells. Moreover, the depletion of GTP concentrations by tiazofurin is most effective in S-phase enriched HL-60 cells. These results may be utilized in cancer chemotherapy to combine tiazofurin with biologic response modifiers which recruit quiescent leukemic cells into the cell cycle.

Effect of the calcium entry blocker nimodipine on the metabolism of nucleic acids in rat brain ischemia.

The effect of nimodipine, a 1,4 dihydro-piridine calcium entry blocker (200 micrograms/kg), was investigated in rats after definitive ischemia or 2 min of global ischemia (neck tourniquet method). The brains were freeze-clamped at the desired time intervals and subjected to high pressure liquid chromatography analyses for nucleotides and enzymatic lactate estimation. Although in the definitive ischemia (removal of the brain) no difference was observed in the treated versus the untreated animals, there was a statistically significant difference in both groups after global ischemia followed by reperfusion. Thirty minutes after reflow the brains of the treated animals contained 1,690 +/- 62 nmol ATP/g as compared to 765 +/- 259 nmol ATP/g in the untreated animals (p less than 0.05). The normal controls amounted to 1,932 +/- 77 nmol ATP/g. Also the adenylate energy charge returned to normal in the treated animals (treated animals and controls 0.69 and 0.72, respectively). From these preliminary data we conclude that nimodipine is able to restore mitochondrial function after ischemia and to maintain a high level of energy-rich phosphates. Thus, calcium entry blockers may be effective in preserving and protecting cerebral tissue from irreversible injury after ischemia.

[Gliadin IgA antibodies in diagnosis of celiac disease in childhood]. / Gliadin-IgA-Antikörper bei der Zöliakie-Diagnostik im Kindesalter.

An enzyme immunoassay kit for the determination of anti-gliadin-IgA antibodies in serum has been evaluated in the diagnosis of coeliac disease in childhood. 84 patients, 22 of them with coeliac disease according to ESPGAN's criteria were tested between 1978 and 1989 and the results have been correlated with the findings on small intestine biopsy and the clinical features. The sensitivity of the test was 95.5% and the specificity was 87.0% on initial diagnosis. On a gluten-free diet reduced antibody levels were seen in all patients. During gluten challenge 11 of 13 children showed an increase in anti-gliadin-IgA concentration. Of the remaining 2 without antibody elevation IgA deficiency became manifest in one patient, the other had a nearly normal mucosa on small intestine biopsy. Provided that IgA deficiency is ruled out and the gluten intake is sufficient the test seems to be useful for screening and might replace biopsy after gluten challenge in cases of increasing antibody levels.

[Clinical experiences with an antimycotic foam preparation with added prednisolone (Nystacorton foam)]. / Klinische Erfahrungen mit einem antimykotischen Schaumpräparat mit Zusatz von Prednisolon (Nystacorton Schaum).

Twenty-five infants and children with Candida infections in the perianal, genital and inguinal areas and on the skin normally covered by the napkin or diaper, confirmed by culture tests and microscopy, were treated with a new combined foam preparation containing the active substances nystatin, chlorhexidine and prednisolone. Even partially very severe lesions with multiple, satellitelike colonies on the trunk, extremities and neck were, without exception, cured within a maximum of 13 days. After disappearing of the exudative stage, intermittent treatment with a rather more greasy excipient (Excipial Cream) containing no active substance, has proved beneficial.

[Mucocutaneous lymph node syndrome or infantile perlarteritis nodosa with extensive vascular involvement]. / Mucocutanes Lymphknoten-Syndrom oder Infantile Periarteritiitis nodosa mit ausgedehnter Gefässbeteiligung.

The authors report on a male infant displaying all the clinical features of the mucocutaneous lymph node syndrome (MLNS) as described by Kawasaki in 1967. In the same patient, diffuse dilatation of the whole arterial tree--as known in infantile periarteriitis nodosa but so far not shown in MLNS--could be demonstrated angiographically during the acute phase of the disease. As the vascular findings at postmortem examination in MLNS and periarteriitis nodosa were the same too, the authors believe that separation of these diseases is not justified.

Studies of purine and tiazofurin metabolism in drug sensitive human chronic myelogenous leukemia K 562 cells.

Antineoplastic activity of tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide) is mediated by an anabolite of the drug thiazole-4-carboxamide adenine dinucleotide (TAD), an analog of NAD which inhibits IMP dehydrogenase activity resulting in the depletion of guanylate pools and cell death. Human chronic myelogenous leukemia K 562 cells were found to be sensitive to tiazofurin with an IC50 of 19.2 microM. TAD content in K 562 cells (1.3 nmol/10(9)/h) was in the range found in susceptible murine and human tumor cells. Studies were conducted to relate tiazofurin toxicity with biochemical effects by examining nucleotide pools. Among the nucleotides, only guanylate pools were significantly depleted by the drug. To further study the effect of the drug on the purine nucleotide de novo and salvage biosynthetic pathways, flux of radiolabelled formate and guanine was employed. The results showed that de novo synthesis of guanylates was curtailed primarily by the drug's action without influencing adenylate biosynthesis or salvage of guanine to guanylates. These studies show that K 562 cells are sensitive to selective inhibition of de novo guanylate pathway indicating that human chronic myelogenous leukemia in blast crisis might be a good candidate for Phase II clinical trials with tiazofurin.

[Fronto-basal cerebrospinal fluid fistula. Diagnosis and its significance in the etiology of mixed purulent meningitis]. / Die frontobasale Liquorfistel. Ihre Diagnostik und ihre Bedeutung für die Entstehung von Meningitis-purulenta-Mehrfacherkrankungen.

By means of own clinical observations and reports from the literature we want to emphasize the clinical importance of early diagnosis of abnormal communications between the subarachnoid space and other body compartments. Clinical symptoms of these conditions are rather sparse; the diagnosis has to be made therefore by a high index of suspicion. The most relevant criteria for further investigation of a cerebrospinal fluid fistula are in summary: Recurrent purulent meningitis. Sometimes a considerable time interval between the first episode of purulent meningitis and further disease states can be observed. History of trauma to the bony structure encasing the central nervous system and liquorrhea at least sometimes in the past. The trauma may have occurred sometimes in early childhood or infancy and thought to be trivial. A positive culture of pneumococci in the cerebrospinal fluid is the least characteristic sign. Some patients are partially treated with antibiotics before the diagnosis is made and this might prove sufficient, not to culture organisms in the cerebrospinal fluid. In case of a recurrent meningitis a further investigation has to be done to arrive at a satisfactory explanation. A cerebrospinal fluid fistula has to be excluded by all means. If a fistula is found, further recurrences can be prevented only if the abnormal communication is closed surgically.